Complex metal salts of alkylphenolaldehyde condensation products and method for preparing same



United States Patent No. 24,666 14 Claims. (Cl. 260-53) This invention relates to a new class of additives useful as motor oil detergents and to a method for preparing these additives.

It is well known that lubricating oils tend to deteriorate under the conditions of use in present day diesel and automotive engines with attendant formation of sludge, lacquer and resinous materials which adhere to the engine parts, particularly the piston ring grooves and skirts, thereby loweringthe operating efficiency of the engine. To counteract the formation of these deposits, certain chemical additives have been found which when added to lubricating oils have the ability to keep the deposit-form mg materials suspended in the oil so that the engine is kept clean andin efficient operating condition for extended periods of time. These addition agents are known in the art as detergents of dispersants. Metal organic compounds, particularly metal salts of organic acids, are useful in this respect. It has been shown furthermore that such salts prepared by processes which enable the incorporation of excess amounts of metal therein, i.e., amounts over and above that required to form normal salts, exhibit markedly improved ability as detergents for lubricating oils, particularly oils employed in the lubrication of engines using high sulfur-content fuels. Methods whereby the advantageous excess amounts of metal are incorporated into the detergent salts are, therefore, of great value to the art. These high metal-content salts are generally termed complex salts for the reason that the excess metal is believed to be incorporated therein through some type of complexing mechanism,.such as occurs in the formation of Werner Coordination Compounds. The present invention is concerned with the provision of such a process. Thus, by the process of this invention, it is possible to prepare complex metal salts of alkylphenolformaldehyde condensation products having incorporated therein from about 50 to about 100% excess metal and which are highly effective motor oil detergents. These salts have also been found to be effective antioxidants for such oils. n

As far as is known the high metal-content fcomplex. salts of this invention have not been produced heretofore and they are therefore, believed to be new compositions of matter. Accordingly, it is the primary object of this invention to provide anew process for the preparation of high metal-content salts of alkylphenol-formaldehyde products. I

It is a further object of the invention to provide a new class of high metal-content salts. It is a still further ob -ject to provide mineral lubricating oil compositions of such methods depends not only upon the conditions and techniques employed but is apt to vary with the particular metal sought to be incorporated into the complex salt product. Thus, it has been found that a method whereby the complex salt of one metal can be successfully prepared is oftentimes unsuccessful when applied to the preparation of a salt of a different metal. It is seen then that the metals, even metals of the same group in the periodic table, are not equivalent in their ability to form high metal-content complex salts.

It has been found that the method of the present invention can be successfully employed to prepare high metal-content salts of the metals barium, strontium, sodium, and potassium, but is not capable of producing complex salts having any substantial excess of other metals such as calcium, magnesium and zinc. This invention, therefore, is directed specifically to the preparation of complex salts of barium, strontium, sodium and potassium, the only metals which have been found to provide such salts by the application of the method.

Broadly stated, the method of the invention involves the interaction of (a) an alkylphenol of a defined type, as set forth hereinafter, (b) formaldehyde, (0) a carboxylic acid selected from formic acid and hydroxyacetic (glycolic) acid and (d) a metal hydroxide of barium, strontium, sodium or potassium, in a suitable solvent medium, such as a mineral oil, at a temperature of from about 40 to about C. followed by dehydration to remove water of reaction and final filtration to remove insolubles, such as excess salt reagent and the like. it has been found that other carboxylic acids, such as acetic acid, and dicarboxylic acids, such as oxalic acid, do not provide the desired complex salts when used in the process of the invention as do formic and glyco-lic acids.

A modification of the process involves subjecting the reaction mixture, prior to final filtration, to treatment with carbon dioxide. This treatment, however benefits the process only with respect to the preparation of the barium and strontium salts of the invention and is not of advantage when applied to the preparation of the sodium and potassium salts, as will be explained hereinafter.

A preferred procedure for carrying out the process of the invention is as follows. The alkylphenol, formalde hyde, formic acid or hydroxyacetic acid and metal hydroxide reagents are brought together in a suitable solvent, such as mineral oil. The solvent mixtureis then heated with stirring to a moderately elevated temperature, say, about 40 to about 85 C. and maintained at this temperature for about one hour. Thereafter, the temperature of the reaction mixture is raised to at least about 0., preferably about 200 C., and maintained at this temperature until all or the water of reaction has been driven off. The hot reaction mixture is then filtered to remove insoluble material, such as excess salt reagent. Asindi cated previously, in the preparation of the barium and strontium complex salts the reaction mixture, prior to filtration, may be treated with carbon dioxide. In the case of the barium and strontium salts, it has been found that, the carbonation effects a substantial increase in the metal contents of the product salts and at the same time increases the fluidity of the product mixture so that filtration and handling of the product is greatly facilitated. Furthermore, it has been found that the carbonation treatment neutralizes the strong base constituents present in the barium and strontium complex salts without, however, reducing their high reserve alkalinity, which is particularly desirable if the salts are to be added to lubricating oils for use in engines burning high sulfur-content fuels. With respect to the preparation of the sodium and potassium complex salts, however, it has been found that the carbonation treatment tends to reduce rather than increase the metal contents of the product salts. For this reason, and because these salts are not highly viscous, the use of the carbonation step is not prescribed for the preparation of these salts.

Although it is generally preferred to use a mineral lubricating oil as the solvent, it will be appreciated that other solvents may be used in the process of the invention. Thus, any inert hydrocarbon solvent having a sufficiently high boiling point (above about 150 C.), such as a naphtha fraction or the like may be used. In such case, the solvent may be removed from the product salt by distillation or the product salt may be retained therein for convenience in handling, shipping, etc. How ever, the use of a mineral lubricating oil as solvent is preferred as it need not be removed from the product prior to use, the concentrated oil solution being directly blendable with the lubricating oil stock desired to be fortified by addition of the complex salt product thereto.

Although the above-described procedure for carrying out the process of the invention is preferred, other modes of operation are entirely satisfactory and may be employed. Thus, the order in which the reactants are brought together may be varied as follows: (1) The alkylphenol, formaldehyde and barium hydroxide reagents may be added to the mineral oil solvent and the mixture heated after which the formic or hydroxyacetic acid is added; (2) The alkylphenol, formaldehyde and formic or hydroxyacetic acid may be added to the mineral oil and the mixture heated after which the barium hydroxide is added; (3) The alkylphenol-formaldehyde condensation product can be formed separately after which the barium hydroxide and the acid reagents are added; and (4) The alkylphenol, formaldehyde and barium hydroxide can be added to the oil and the mixture reacted, dehydrated and filtered, after which the acid reagent is added.

Broadly, the ratios of reagents employed in the process of the invention are as follows. For each mole of alkylphenol (a) about 1.3 moles of formaldehyde, (b) from about 0.85 to about 2.0 moles of metal hydroxide when the metal is barium or strontium and from about 1.70 to about 4.0 moles of metal hydroxide when the metal is either sodium or potassium and (c) from about 0.5 to about 1.0 mole of formic or hydroxyacetic acid; the preferred ratios being (a) about 1.0 mole of formaldehyde, (b) about 1.1 moles of either barium or strontium hydroxide and about 2.2 moles of either sodium or potassium hydroxide and about 0.5 mole of formic acid or glycolic acid per mole of alkylphenol.

When the carbonation treatment is employed, the amount of carbonation required is small. Thus, it has been found that the first introduction of carbon dioxide effects a marked improvement in the fluidity of the reaction mass. Generally, however, in order to provide products of reduced strong alkalinity, the carbon dioxide is used in amounts sufi'icient to incorporate from about 0.1 to about 0.7 mole of carbon dioxide per mol of alkylphenol in the complex salt product.

With respect to the amount of metal hydroxide reagent used in the process, it has been found that the use of amounts higher than those mentioned hereinabove usually results in filtration difficulties.

As already stated, the initial reaction temperature (i.e., prior to the dehydration step) is from about 40 to about 85 C. A reaction time of about one hour at this temperature is generally allowed in order to insure completion of the reaction. For the dehydration step, the temperature of the reaction mixture is increased to above 100 C., and preferably to ISO-200 C., due to the fact that at lower temperatures than 150 C. the reaction mixture is apt to be quite viscous. Also the higher dehydration temperatures insure relatively rapid and thorough removal of the water. Also, it is preferred to conduct the carbonation treatment at the 200 C. level as ithas been found in the case of the barium and strontium salts, that carbonation at this temperature effects about a 12% increase in the metal content of the complex salt products over that provided by carbonation at 150 C. The time of carbonation will, of course, vary depending upon the size of the reaction mass, the rate of introduction of the carbon dioxide, the efliciency of contacting,

etc. Accordingly, although the examples presented here-- inafter show carbonation times varying between about 2 and about 8 hours, it should be appreciated that the required carbonation time could be longer or shorter de-- pending upon the type of reactor used, etc.

The alkylphenols suitable for use in the invention comprise the mono-alkyl-substituted phenols in which the alkyl substituent group contains from about 8 to about 18 carbon atoms. Alkylphenols having alkyl substituents of less than 8 carbon atoms generally do not provide complex salts which are oil-soluble. Specific examples of suitable alkylphenols are the following: mono-octyl phenol, mono-nonyl phenol, mono-decyl phenol, monododecyl phenol, mono-tetradecyl phenol, mono-hexadecyl phenol and mono-octadecyl phenol.

It has been found that when dialkyl-substituted phenols are employed in the process of the invention, the metal contents of the salt products are not significantly greater than those of the normal salts. The method of the invention, therefore, is specific to the mono-alkylphenols, although a crude grade of alkylphenols consisting of a mixture of monoand di-alkylphenols, and containing predominantly mono-alkylphenols, has been found to give complex salt products. The metal contents of these salts, however, are not as high as those obtained using a commercial grade of mono-nonyl phenol.

The exact nature of the complex barium salts of the invention is not presently known. Without intending to limit the invention by theoretical considerations, however, it is believed that the salt product is a complex of metal formate, hydroxide, carbonate or bicarbonate bonded to the phenate salt by coordinate bonds of the type found in Werner Coordination Compounds.

The following examples will serve to fully illustrate the invention. In these examples both the percentage metal content (found by actual analysis) and the percentage of excess metal (calculated on the basis of the theoretical content of the corresponding normal salt) in each instance are shown for each of the complex salt products. Thus, for example, excess means that the metal content of the complex salt product is twice as great as that of the corresponding normal metal salt. In certain of the examples, however, in which the metal content of the product salt was less than the theoretical metal content of the normal salt, the percentage of theoretical metal content (percent of theory) is shown along with the actual percentage metal content. These latter examples illustrate preparations outside the scope of this invention.

' EXAMPLE 1 Reagents Charged grams (0.5 mole) of nonylphenol 42 grams (0.5 mole) of formaldehyde (36% solution) 185 grams (0.58 mole) of barium hydroxide octahydrate 23 grams (0.5 mole) of formic acid (98%) 330 grams of conventional parafiin oil (100 sec. at

Procedure All of the materials were mixed in a three-liter, fourneck flask equipped with a mechanical stirrer, thermometer, nitrogen inlet tube, Dean-Stark water take-off and reflux condenser. The reagents were mixed and heated to 5055 C. for one hour. Nitrogen was then applied, the heat increased and water distilled from the reaction mixture until a temperature of 200 C. was reached. This temperature was maintained for one hour to insure complete dehydration. About grams of this material was removed and filtered through a Hyfid (a diatomaceous earth filter aid) precoated, electrically heated Buchner funnel to yield a viscous product.

Product Analysis Barium, percent 11.69 (86% excess). Potentiometric base number--. 87 (total), 53 (strong).

EXAMPLE 2 Procedure The remainder of the reaction product prepared in Example 1 was treated prior to filtration for eight hours at 200 C. with a stream of carbon dioxide gas. The resulting material was cooled and filtered in the usual manner yielding a greenish oil of low viscosity.

Product Analysis Barium, percent 12.17 (94% excess). Potentiometric base number 84 (total), 39 (strong). Formic acid, percent e 2.73. Carbon dioxide, percent 1.40. Specific gravity at 26 C 1.050.

EXAMPLE 3 Reagents Charged All of the materials of group (A) were mixed and heated at 4060 C. for one hour in a one-liter, fourneck, round-bottom flask equipped with a mechanical stirrer, thermometer, nitrogen inlet tube and Dean-Stark Water take-offwith reflux condenser. The formic acid (B) was added to this mixture over a twenty minute period at 6070 C. Water was then removed by distillation until a maximum temperature of 150 C. was reached. This temperature was held for one hour, after which a 100 gram sample was removed and filtered in the normal manner. The remainder of the material was carbonated for 2.5 hours at 200 C. and filtered by th conventional method.

Product Analysis Barium, percent 12.30 (96% excess). Potentiometric base No 83 (total), 19 (strong). Kinematic viscosity at 210 F., cs 13.34. Formic acid, percent 1.83. Carbon dioxide, percent 2.54. Specific gravity at 24 C 1.053.

EXAMPLE 4 Reagents Charged 550 grams (2.5 moles) of nonylphenol 1650 grams of conventional paraflin oil (100 sec. at

870 grams (2.75 moles) of barium hydroxide octahydrate 208 grams (2.5 moles) of formaldehyde (36% solution) 70.5 grams (1.25 moles) of formic acid (88-90%) Procedure 8 Product Analysis Barium, percent 12.27 (95% excess). Potentiometric base number 85 (total), 25 (strong). K.V. at 210 F., cs 12.00. Formic acid, percent 1.68. Carbon dioxide, percent 2.21.- Specific gravity at 26 C 1.051.

EXAMPLE 5 Procedure The portion of uncaroonated product retained in Example 4 was carbonated at 150 C. for 2 hours by the conventional procedure.

Product Analysis Barium, percent 10.86 (72% excess).

It is seen that the longer carbonation (3 hours) at the higher temperature (200 C.) employed in Example 4 produced a complex salt of higher barium content than obtained in this example.

EXAMPLE 6 In this example,a mixture of 20 mole percent of di nonylphenol and 80 mole percent of nonylphenol was used and 'gave a satisfactory metal retention.

- Reagents Charged 88 grams (0.4 mole) of nonylphenol 34 grams (0.1 mole) of dinonylphenol 174 grams (0.55 mole) of barium hydroxide octahydrate 45 grams (0.55 mole) of formaldehyde (36% solution) 12.6 grams (0.25 mole) of formic acid (88-90%) 330 grams of conventional paraffin oil (100 sec. at

Procedure Barium, precent 12.94 (109% excess) Potentiometric base number"--. 96 (total), 28 (strong). Kinematic viscosity at 210 F., cs 16.27. Formic acid, percent 1.41. Carbon dioxide, percent 3.09.

EXAMPLE 7 The procedure was the same as that described in Exwas withdrawn for use in Example 5. The carbonation was then carried out for 3 hours at 200 C.

This example illustrates the use of a crude grade of nonylphenols. It is seen that lower metal content re sults from the use of this phenol in place of the commercial grade of monononylphenol;

Reagents Charged 236 grams (1.0 mole, based on hydroxyl number) of technical nonylphenol 472 grams of conventional parafiin oil sec. at

100 F.) 90 grams 1.0 mole) of formaldehyde (36% solution) 25.2 grams (0.5 mole) of formic acid (88-90%) 347 grams (1.1 moles) of barium hydroxide octahydrate Procedure The identical procedure was used as in the preparation of Example 1, exceptthat a maximum dehydration temperature of C. was used. Carbonation was done conventionally at 200 C. for 2.5 hours. 1 a

used during dehydration. carbonation was used by treating with carbon dioxide for 7 Product Analysis Barium, percent 13.31 (70% excess). Potentiometric base number 112 (total), 23 (strong). K.V. at 210 F., cs 17.44. Formic acid, percent 2.64. Carbon dioxide 3.01.

EXAMPLE 8 Reagents Charged 172 grams (0.5 mole) of dinonylphenol 344 grams of conventional paraffin oil (100 sec. at 100 25.5 grams (0.3 mole) of formaldehyde (36% solution) 174 grams (0.55 mole) of barium hydroxide octahydrate 28.3 grams (0.5 mole) of formic acid (88-90%) The same procedure was used as described in Example 1 except that the maximum dehydration temperature was 150 C. Carbonation was conventional and was for 3.5 H

hours at 200 C.

Product Analysis Barium, percent 2.47 of theory). Potentiometric base number 18 (total), 6.4 (strong). K.V. at 210 C., cs 6.40.

Another preparation using 1.0 mole of formaldehyde and 0.5 mole of formic acid per mole of dinonylphenol gave a barium content of 3.2% (37% of theory).

EXAMPLE 9 Reagents Charged The same procedure was used as described in Example 1, except that a maximum temperature of 150 C. was The conventional method of 3 hours at 200 C.

Product Analysis Barium, percent 11.2 (79% excess). Potentiometric base number 80 (total), 24 (strong). K.V. at 210 F., cs 12.90.

Glycolic acid, percent 1.75.

Carbon dioxide, percent 2.11.

EXAMPLE 10 Reagents Charged 131 grams (0.5 mole) of dodecylphenol 393 grams of conventional parafiin oil (100 sec. at

174 grams (0.55 mole) of barium hydroxide octahydrate 12.6 grams (0.25 mole) of formic acid, 88-90% 42 grams (0.5 mole) of formaldehyde, 39% solution Procedure The same as that used in Example 1, except that a maximum dehydration temperature of 150 C. was used.

Product Analysis Barium, percent 8.98 (58% excess). Potentiometric base number (total),

48 (strong).

Kinematic viscosity at 210 F., cs 24.13.

. EXAMPLE 11 A portion of unfiltered material, prepared in Example 10, was carbonated by the conventional procedure for 5 hours at 200 C.

Product Analysis Barium, percent 9.63 (70% excess). Potentiometric base number 64 (total),

- 18 (strong). Kinematic viscosity at 210 F., cs 9.38.

EXAMPLE 12 In this example paraformaldehyde was substituted for the formaldehyde solution used in the preferred procedure.

Reagents Charged grams (0.5 mole based upon tthe theoretical molecular weight) of nonylphenol 15 grams (0.5 mole) of paraformaldehyde 12.1 grams (0.25 mole) of formic acid, 88-90% 174 grams (0.55 mole) of barium hydroxide octahydrate 330 grams of conventional paraflin oil (100 sec. at

Carbn dioxide Procedure The same preparative method was used as described in Example 1, with the exception of the use of a maximum dehydration temperature of C. This material was then carbonated by the usual method for 3 hours at 200 C.

Product Analysis Barium, percent 12.2 (96% excess).

Potentiometric base number 75 (total),

22 (strong). Kinematic viscosity at 210 F., cs. 13.19.

EXAMPLE 13 (a) This example illustrates successful utilization of a preformed alkylphenol-formaldehyde resin to give a complex salt product of thedesired type. Ammonium hydroxide was used as the catalyst for the phenol-formaldehyde condensation reaction.

Reagents Charged 880 grams (4 moles based upon the theoretical molecular weight) of nonylphenol 2460 grams of conventional paraffin oil 360 grams (4.0 moles) of formaldehyde, 36% solution 20 ml. of ammonium hydroxide, 29.0% NHg Procedure All of the reagents were mixed in a five-liter, fourneck, round-bottom flask equipped with a mechanical stirrer, thermometer, nitrogen inlet tube and Dean-Stark water take-elf with reflux condenser. The temperature was maintained in the range of 50-70 C. for one hour. Water was removed by distillation to a maximum temperature of 150 C. This temperature was held for two holurs. The product was slightly viscous and yellow in co or.

Product Analysis Nitrogen, percent 0.14. Specific gravity at 28 C 0.900. Kinematic viscosity at 210 F., cs 4.78. Hydroxyl No 74 (calculated==60).

Viscosity measurements on an oil blend of nonylphenol to give a comparable concentration gave the following results: Kinematic viscosity at 210 F., cs.=3.87.

EXAMPLE 13(b) Reactants Charged 447 grams (0.5 mole) of condensation product prepared in Example 13(a) product.

174 grams (0.55 mole) of barium hydroxide octahydrate 12.1 grams (0.25 mole) of formic acid, 88-90% .Carbon dioxide Procedure The materials listed were charged into a two-liter, fourneck flask equipped with a mechanical stirrer, nitrogen inlet tube, thermometer, Dean-Stark water take-off tube and reflux condenser. The reaction mixture was stirred for one hour at a temperature of 80 C. to 100 C. for 30 minutes. Water was removed by distillation to a temperature of 150 C. This temperature was held for one hour to insure dryness. then treated by the conventional procedure with carbon dioxide for 3 hours at 200 C.

Product Analysis Barium, percent 11.6 (86% excess). Potentiometric base number 81 (total), 27

(strong).

Kinematic viscosity at 210 F.,

cs 8.24. Formic acid, percent 2.29. Carbon dioxide, percent 2.20. Specific gravity, at 28 C 1.041.

EXAMPLE 14 This example also illustrates the utilization of the pre formed phenol-formaldehyde condensation product, but here formic acid is employed as .the catalyst for the condensation. The formic acid remains in the reaction mixture and is ultimately incorporated into the complex salt Reagents Charged All of the materials in group (A) were added to a oneliter, four-neck flask equipped with a mechanical stirrer, thermometer, nitrogen inlet tube, Dean-Stark take-off and reflux condenser. The reaction mixture was heated at 7080 C. for one hour, to eifect the phenol-formaldehyde condensation, then the hydroxide (B) was added. 5

This mixture was dehydrated to a temperature of 150 C. and held at this temperature for one hour. The re action mixture was then treated with carbon dioxide in the usual manner for 2 hours at 200 C.

Product Analysis Barium, percent 10.6 (68% excess). Potentiometric base number 69 (total), 13 (strong). Kinematic viscosity at 210 F.,

A product prepared in the same manner as Example 14, except that formaldehyde solution was substituted for the paraformaldehyde, gave the following analysis:

Barium, percent 10.5 (66% excess). Potentiometric base number 71 (total), 21

(strong). Kinematic viscosity at 210 F., cs... 8.81.

EXAMPLE 15 This example illustrates the preparation of a complex salt of the invention by the reaction of formic acid with the carbonated product salt formed from the reaction of nonylphenol, formaldehyde and barium hydroxide.

The reaction mixture was Reagents Charged 220 grams (1.0 mole) of nonylphenol 84 grams (1.0 mole) of formaldehyde (36% solution) 347 grams (1.1 moles) of barium hydroxide octahydrate 660 grams of conventional paraflin oil sec. at

Procedure The same procedure was used as in Example 1 except that the unfiltered product mixture was reacted with CO by the conventional procedure at 200 C. for 5 hours and filtered.

To a 100-gram portion of the product thus obtained, 2.5 grams (0.5 mole) of formic acid (8890%) was added dropwise over a twenty minute period at l20150 C. to the filtered reaction product contained in a one-liter, four-neck, round-bottom flask equipped with a mechanical stirrer, dropping funnel, Dean-Stark water take-off, reflux condenser, thermometer and nitrogen inlet tube. This reaction mixture was then heated to 200 C. to insure dryness. The product was cooled and filtered through a Buchner funnel (electrically-heated) to yield a viscous, yellowish-brown oil.

Product analysis Barium, percent 13.1 (102% excess). Formic acid, percent 2.55. Carbon dioxide, percent 2.33. Potentiometric base number 94 (total), 26

(strong). Kinematic viscosity at 210 F., cs 17.38.

EXAMPLE 16 Reagents Charged grams (0.5 mole) of nonylphenol 71.8 grams (1.1 moles) of potassium hydroxide, 86% 45 grams (0.53 mole) of formaldehyde, 36% solution 12.5 grams (0.25 mole) of formic acid, 88-90% 330 grams of conventional paraflin oil (100 sec. at

, Procedure The same procedure was used as was shown in Example 1, except that a dehydration temperature of C.

. was used.

Product Analysis Potassium, percent 7.19 (100% excess). Potentiometric base number 101 (total), 69

(strong). Kinematic viscosity at 210 F., cs..- 17.72.

Formic acid, percent 4.01.

EXAMPLE 17 Reagents. Charged 220 grams (1.0 mole) of nonylphenol 91 grams (2.2 moles) of sodium hydroxide, 97.4%

90 grams (1.05 moles) of formaldehyde, 36% solution 25 grams 0.5 mole) of formic acid, 88-90% 660 grams of conventional paraflin oil (100 sec. at

100 F.) Procedure This was the same as that used in Example 1, except that the maximum dehydration temperature of 150 C. was used. V

Product Analysis Sodium, percent 3.70 (74% excess).. Potentiometric base number 89.

Kinematic viscosity at 210 F., cs 13.59.

The utility of the complex salts of this invention as lubricating oil additives has been demonstrated by comparative tests conducted on base lubricating oils alone and 5 these same oils blended with minor amounts of repre- 1i sentative product salts described in the preceding examples. The tests used were the Lauson Engine Test and the Catalytic Oxidation Test.

LAUSON ENGINE TEST This test involves the operation of the single cylinder, 4-cycle, liquid-cooled Lauson engine under the following conditions: oil temperature, 270 R; jacket temperature, 212 F.; speed, 1825 rpm.

The duration of the test is 100 hours and oil is added every 20 hours.

This test determines oil deterioration as primarily indicated by engine cleanliness. The engine which is clean at the start of the test is inspected after the test run for cleanliness of the rings, lands, ring grooves and piston skirt. Cleanliness ratings are made, based on a scale of from 100 to zero, a rating of 100 signifying a perfectly clean engine and a rating of zero representing the worst possible deposit condition.

The cleanliness rating obtained for the oil blend is compared to that found in a test employing the base oil alone, i.e., without addition of the additive.

In a test of a typical complex salt product of the invention, viz., the complex carbonated barium formatenonylphenolformaldehyde salt of Example 4, the base oil shows a cleanliness rating of 63, while the oil blend containing 2.45% (0.3 barium) of the complex salt showed a cleanliness rating of 85.

It has been found that besides their ability as detergents, the complex salts of the invention are also highly effective antioxidants for lubricating oils. This has been shown by subjecting several of the salt products .to the Catalytic Oxidation Test.

CATALYTIC OXIDATION TEST (C.O.T)

This test determines the effectiveness of an additive in preventing catalytic oxidation of an oil. The test procedure is as follows. In a 200 x 25 mm. test tube is placed a 25 cc. sample of test oil having immersed therein (a) 15.6 sq. in. of sandblasted iron wire, (b) 0.78 sq. in.

of polished copper wire, 0.87 sq. in. of polished alu minum Wire and (d) 0.167 sq. in. of polished lead surface. The oil is heated to a temperature of 260 F. and maintained at this temperature, while drying air is being passed therethrough, at a rate of 18 liters per hour, for V 40 hours. The results of the test are reported in terms of Stability Number of the additive. The Stability Number is the percentage of additive (in the oil) multiplied by 100, that reduces the N.N. (Neutralization Number) of the reference oil to a value of 2. Thus, the lower the ad- TABLE I Percent metal Additive (Ex. N0.) in additive It will be appreciated that the complex salt products, as provided by the process of this invention, are ordinarily concentrated oil solutions of the complex salts, these solutions containing from about 30% to about 70%, by weight, of the complex salts, the particular concentration depending upon the process conditions employed, including the amount of solvent oil used in the process, etc. The amount of the product which is added to a petroleum fraction to provide a particular concentration of complex salt therein will, therefore, vary somewhat with a particular product. As a practical matter, however, differences in the products can be readily eliminated by standardization of process conditions and/or final adjustment of the product oil solutions to some standard salt content, as will be readily appreciated by those skilled in the art. Allowing for the usual variations in the salt! contents of the product oil solutions, i.e., from about up to about of complex salt content, the amounts of the products to be utilized as additives in lubricating oil will range broadly from about 0.5% to about 30%, by weight, the usual amount being from about 2% to about 8%.

The additives of the invention may be used in lubrieating oil compositions containing other additives designed to improve various characteristics of the oil, such as pour point depressants, viscosity index improvers, extreme pressure agents, other detergents, etc.

Although the present invention has been described herein by means of certain specific embodiments and illustrative examples, it is not intended that the scope thereof be limited in any way thereby, but only as indicated in the following claims.

This application is a division of application Serial No. 730,528, filed April 24, 1958, and now Patent No. 3,014,868.

What is claimed is:

i. A method for preparing a complex metal salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting about 1 mole of a monoalkylsubstituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof, in the presence of a hydrocarbon solvent, with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of a carboxylic acid selected from the group consisting of formic acid and glyeolic acid and (c) from about 0.85 to about 4.0 moles of a hydroxide of a metal selected from the group consisting of sodium, potassium, barium and strontium, the amount of said metal hydroxide being from about 1.70 to about 4.0 moles in the case of potassium and sodium hydroxides and from about 0.85 to about 2.0 moles in the case of barium and strontium hydroxides, at a temperature of about 40 C. to about C., (2) heating the reaction mixture from step 1 at a temperature of at least about C. to substantially completely dehydrate said mixture and (3) filtering off insoluble material.

2. A method for preparing a complex barium salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of barium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) filtering ofif insoluble material.

3. A method for preparing a complex barium salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting an oil solution of a monoalkyl substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of barium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove Water therefrom, (3) treating the heated 13 reaction mixture from step 2 with carbon dioxide and (4) filtering off insoluble material.

4. A method for preparing a complex strontium salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 mole of formaldehyde, (b)from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of strontium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) filtering off insoluble material.

5. A method for preparing a complex strontium salt of an alkylphenol-formaldehyde condensation productwhich comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of strontium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom, (3) treating the heated reaction mixture from step 2 with carbon dioxide and (4) filtering off insoluble material.

6. A method for preparing a complex potassium salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from. about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 1.7 to about 4.0 moles of potassium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove Water therefrom and (3) filtering off insoluble material.

7. A method for preparing a complex sodium salt of an alkylphenol-formaldehyde condensation product which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 13 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 1.7 to about 4.0 moles of sodium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) filtering off insoluble material. 1

8. A complex metal salt of an alkylphenol-formalde hyde condensation product prepared by the method which comprises (1) reacting about 1 mole of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof, in the presence of a hydrocarbon solvent, with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of a carboxylic acid selected from the group consisting of formic acid and glycolic acid and (c) from about 0.85 to about 4.0 moles of a hydroxide of a metal selected from the group consisting of sodium, potassium, barium and strontium, the amount of said metal hydroxide being from about 1.70 to about 4.0 moles in the case of potassium and sodium hydroxides and from about 0.85 to about 2.0 moles in the case of barium and strontium hydroxides, at a temperature of about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely dehydrate said mixture and (3) filtering off insoluble material.

9. A complex barium salt of an alkylphenol-formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkylsubstituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof With'(a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of barium hydroxide, at a temperature of from about 40 C. to about C., (2) heating the reaction mixture from step 1 at a temperature of at least about C. to substantially completely remove water therefrom and (3) filtering off insoluble material.

10. A complex barium salt of an alkylphenol formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkyl substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of barium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom, (3) treating the heated reaction mixture from step 2 with carbon dioxide and (4) filtering off insoluble material.

11. A complex strontium salt of an alkylphenol-formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of strontium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) filtering off insoluble material.

12. A complex strontium salt of an alkylphenol-formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 0.85 to about 2.0 moles of strontium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove Water therefrom, (3) treating the heated reaction mixture from step 2 with carbon dioxide and (4) filtering off insoluble material.

13. A complex potassium salt of an alkylphenol-formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldehyde, (b) from about 0.5 to about 1.0 mole of formic acid and (c) from about 1.7 to about 4.0 moles of potassium hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) filtering off insoluble material.

14. A complex sodium salt of an alkylphenol-formaldehyde condensation product prepared by the method which comprises (1) reacting an oil solution of a monoalkyl-substituted phenol having from about 8 to about 18 carbon atoms in the alkyl substituent group thereof with (a) from about 0.5 to about 1.3 moles of formaldei5 1 5 hyde, (b) from about 0.5 to about 1.0 mole of formic References Cited in the file of this patent acid and (c) from about 1.7 to about 4.0 moles of so- UNITED STATES PATENTS diurn hydroxide, at a temperature of from about 40 C. to about 85 C., (2) heating the reaction mixture from 36, 01 Nefi Feb. 28, 1956 step 1 at a temperature of at least about 150 C. to substantially completely remove water therefrom and (3) FOREIGN PAIENTS filtering off insoluble material. 440,110 Great Britain 1 

1. A METHOD FOR PREPARING A COMPLEX METAL SALT OF AN ALKYLPHENOL-FORMALDEHYDE CONDENSATION PRODUCT WHICH COMPRISES (1) REACTING ABOUT 1 MOLE OF A MONOALKYLSUBSTITUTED PHENOL HAVING FROM ABOUT 8 TO ABOUT 18 CARBON ATOMS IN THE ALKYL SUBSTITUENT GROUP THEREOF, IN THE PRESENCE OF A HYDROCARBON SOLVENT, WITH (A) FROM ABOUT 0.5 TO ABOUT 1.3 MOLES OF FORMALDEHYDE, (B) FROM ABOUT 0.5 TO ABOUT 1.0 MOLE OF A CARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF FORMIC ACID AND GLYCOLIC ACID AND (C) FROM ABOUT 0.85 TO ABOUT 4.0 MOLES OF A HYDROXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF SODIUM, POTASSIUM, BARIUM AND STRONTIUM, THE AMOUNT OF SAID METAL HYDROXIDE BEING FROM ABOUT 1.70 TO ABOUT 4.0 MOLES IN THE CASE OF POTASSIUM AND SODIUM HYDROXIDES AND FROM ABOUT 0.85 TO ABOUT 2.0 MOLES IN THE CASE OF BARIUM AND STRONTIUM HYDROXIDES, AT A TEMPERATURE OF ABOUT 40*C. TO ABOUT 85*C., (2) HEATING THE REACTION MIXTURE FROM STEP 1 AT A TEMPERATURE OF AT LEAST ABOUT 150*C, TO SUBSTANTIALLY COMPLETELY DEHYDRATE SAID MIXTURE AND (3) FILTERING OFF INSOLUBLE MATERIAL. 